In modern day manufacturing facilities, there is a need for an improved parts and materials supply system to minimize inventory and the floor space required for parts storage at the work stations. The efficiency and economy of the so-called "just in time" inventory control system is now well recognized. This inventory control system has the goal of reducing process inventory at work stations as well as back up inventory to levels that will meet the assembly requirements for just a fraction of the work shift. In this system, suppliers deliver incoming materials and parts just prior to assembly or processing time to eliminate the need for in-plant storage on pallets or in bulk containers. There is a need for an automated system which requires small quantities of parts with short term storage and which moves the required parts from known locations to the point of use just prior to the time needed.
Manufacturing systems are known which utilize automatically controlled vehicles for moving work pieces from one work station to another. In the Meyer et al U.S. Pat. No. 3,796,163, a workpiece supply system comprises a closed loop trackway on which one or more cars are supported for movement to various work stations such as numerically controlled machine tools. A car carries a pallet on which a work holding fixture is secured and transports the pallet to a computer selected station. At the selected station, the pallet is automatically removed from the car and placed on a positionable table from which the next workpiece to be supplied to the machine is automatically selected and transferred thereto by computer control.
In the Koluch U.S. Pat. No. 3,727,756 a system is described for supplying articles on demand to a production line for assembly of composite articles in which two components of the article are continuously manufactured at independently variable rates and fed through separate lines which merge with each other at an assembly station. This system includes a bank of individual storage cells for units of one component of the article. A demand accumulator is located between the storage cells and the assembly station to continuously supply units to the assembly station in accordance with the demand rate at which the second components of the article are fed to the assembly station.
A general object of this invention is to provide an improved part supply system which overcomes certain disadvantages of the prior art.